The present invention relates to a static pressure air surface stage or a float stage for precision locating use, which is built in precision working machines, precision measuring instruments, semiconductor manufacturing apparatuses.
Conventionally static pressure air bearing guides were often used in this type of XY stage. One example thereof is shown in FIG. 2. A stage portion 13 is placed on the tolerance portion of two movable guides 11, 12 which are orthogonal in different stage with respect to each other. Eight air bearing pads 14 are oppositely disposed between the movable guides 11, 12 so that the movable guides 11, 12 and a surface plate are placed in non-contact relation.
Also, a linear motor 16 for driving the stage portion 13 is mounted at both ends of the movable guides 11, 12.
In a surface stage of such construction as described hereinabove, the respective air bearing pads 14 are secured by two as a unit. The detailed construction of the air bearing assembly portion will be described in FIG. 3. However, as the air gap of the air bearing was an amount as small as 5 through 10 .mu.m and the plane degree of the pad face after the assembling operation required 1 through 2 .mu.m, it was very difficult to adjust the assembling operation of these bearing pads 14, which took more time and required more labor.